Girls can be vicious to one another. Mothers of both victims and perpetrators can ease the sting

Suddenly it seems that everyone is discovering how mean girls can be. But anyone who finds this new or shocking should travel back in time with me to Dryden High School, when a cabal of meanies got yours truly tossed off the cheerleading squad, just because they could. Still, today's mean girls can pick apart your daughter's reputation or hairstyle with lightning speed in instant-message sessions over the Internet or via conference calls.

Lost in all this 21st century-style aggression is the old-fashioned fact that mothers can do something about it. Rosalind Wiseman, author of Queen Bees and Wannabes (Crown...